Steps towards a textile-based transistor : development of the gate and insulating layer

During recent years, intensive research has been carried out in the area of electronic textiles. There is an emerging trend to create garments that host electronic components embedded in the textile substrate, as well as electronic textiles made from yarns or fibers already possessing electronic properties. The creation of passive devices, such as textile electrodes that measure body parameters, has proved successful. However, there is a great need for the development of textiles possessing additional active functions. Accordingly, we investigated the possibility of developing a textile substrate possessing integrated switching and amplification functions by depositing parts of an organic thin-film transistor on fibrous substrates of varying geometries and origins. This article relates the initial steps we employed to develop a textile-based thin-film transistor. It reports the development of a gate layer from the deposition of electroless copper, as well as the deposition of a polyimide dielectric layer using dip coating. Further, it discusses the layer's properties in terms of thickness and electrical characteristics. A copper layer of 350 nm thickness deposited on polyester tape and polyamide fibers displayed excellent electro-conductive properties. A smooth gate dielectric layer was achieved with a polyimide concentration of 15 w% and a withdrawal speed of 50 mm/min. As a result, optimum conditions for producing thin functional gate and dielectric layers were found. The transistor properties, the deposition of a semiconductive layer, and the production of drain and source electrodes remain the focus of future work